CVE-2024-56739
📋 TL;DR
A Linux kernel vulnerability in the RTC subsystem where a failed __rtc_read_time call leads to uninitialized data being processed, potentially causing kernel softlockups. This affects systems using the Linux kernel's RTC timer functionality. Attackers could exploit this to cause denial of service conditions.
💻 Affected Systems
- Linux Kernel
📦 What is this software?
Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →⚠️ Risk & Real-World Impact
Worst Case
Kernel softlockup leading to complete system unresponsiveness requiring hard reboot, potentially causing data loss or service disruption.
Likely Case
System instability, periodic timer malfunctions, and potential denial of service on affected systems.
If Mitigated
Minor performance impact or timer inaccuracies if proper error handling is implemented.
🎯 Exploit Status
Exploitation requires triggering specific RTC timer conditions and may require local access or ability to manipulate RTC hardware.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patches available in stable kernel trees (commits referenced in CVE)
Vendor Advisory: https://git.kernel.org/stable/c/0d68e8514d9040108ff7d1b37ca71096674b6efe
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from official kernel.org or distribution repositories. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.
🔧 Temporary Workarounds
Disable RTC periodic timers
linuxPrevent use of RTC periodic timers that could trigger the vulnerability
echo 0 > /sys/class/rtc/rtc0/wakealarm
Check system for RTC timer usage and disable if possible
🧯 If You Can't Patch
- Monitor system logs for softlockup warnings and RTC errors
- Restrict local user access to systems where RTC functionality is critical
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare with patched versions in kernel git history. Look for specific commit hashes in kernel source.Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes one of the patched commits: 0d68e8514d9040108ff7d1b37ca71096674b6efe or other referenced commits📡 Detection & Monitoring
Log Indicators:
- Kernel softlockup messages in dmesg
- RTC read errors
- Watchdog timeout warnings
Network Indicators:
- None - local vulnerability
SIEM Query:
source="kernel" AND ("softlockup" OR "watchdog" OR "BUG") AND "rtc"🔗 References
- https://git.kernel.org/stable/c/0d68e8514d9040108ff7d1b37ca71096674b6efe
- https://git.kernel.org/stable/c/246f621d363988e7040f4546d20203dc713fa3e1
- https://git.kernel.org/stable/c/39ad0a1ae17b54509cd9e93dcd8cec16e7c12d3f
- https://git.kernel.org/stable/c/44b3257ff705d63d5f00ef8ed314a0eeb7ec37f2
- https://git.kernel.org/stable/c/a1f0b4af90cc18b10261ecde56c6a56b22c75bd1
- https://git.kernel.org/stable/c/dd4b1cbcc916fad5d10c2662b62def9f05e453d4
- https://git.kernel.org/stable/c/e77bce0a8c3989b4173c36f4195122bca8f4a3e1
- https://git.kernel.org/stable/c/e8ba8a2bc4f60a1065f23d6a0e7cbea945a0f40d
- https://git.kernel.org/stable/c/fde56535505dde3336df438e949ef4742b6d6d6e
- https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html
- https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html
